Most modern equipment for implementing telecommunications systems contain one or more electronic apparatus housed in a casing. For example, optical switches can hold multiple, closely spaced, optical cards, enclosed in a casing having a front access door, side walls, and a backplane. Generally, at one end, the optical cards are electrically coupled to the backplane, which performs an interconnect function between the various cards within the casing. In most instances, the optical cards terminate at the other end with connectors for fiber optic cables. The close arrangement of the optics cards and fiber cables within the casing provides a space savings and the advantage of allowing the cards and cables to be removed/inserted independent of one another.
Unfortunately, there are drawbacks to the closely spaced card/fiber cable arrangement, as well. For example, fiber cables are at risk when service work is performed on the equipment, such as installation/removal of cards or fiber cables and/or replacement of equipment components, such as fans, filters, and the like. The fiber cables are typically allowed to dangle from the casing and may become easily dislodged, which may cause unwanted disruption in the service being provided by the equipment. The fiber cables may also become entangled with other equipment systems, which may pose a hazard to technicians and others who work in close proximity to the equipment system. Finally, because of the dangling nature of the fiber cables, undue strain may be placed on the fiber cables, which may cause them to become dislodged, to be chaffed against sharp edges, or else to break.
Installers of optical switching equipment have encountered other drawbacks when routing fiber cables into and out from optical switches. For example, it is often necessary to route fiber cables about sharp corners. Routing fiber cables around sharp corners is inherently problematic, since over time, any movement of the fiber cable relative to the sharp corner may cause chaffing and/or cuts to develop in the fiber cable. It also happens that fiber cables are pulled on during installation or repair with sufficient force so as to deform the fiber cable. Unfortunately, when fiber cables are bent beyond a certain limit (i.e. bend radius) or pulled on with sufficient force, the fiber cable can break or the signal traveling through the cable may be attenuated beyond acceptable operational limits.
The present invention provides a shelf assembly and system, which reduces the potential for accidental disruption of service or damage to neighboring transmission elements in a telecommunications network. The present invention is useful for guiding incoming or outgoing transmission elements, such as optical fiber cables, to and from the telecommunications network. The present invention operates to guide the fiber cables to or from a mounting position, and in or out from either side of electrical and/or optical telecommunications equipment.
The shelf assembly can include a card cage assembly, which defines an interior space for receiving plug-in cards, generally having telecommunications functionality. Each plug-in card includes at least one fiber cable mounting position disposed at a terminal end of the card. Fiber cables coupled at the mounting positions can be directed through reversible and removable fiber channels. In accordance with the present invention, each fiber channel has a smooth surface and a radius of curvature, which provides an appropriate bend radius for guiding, routing, or bending the fiber cables into a fiber trough. The fiber trough provides a pathway to openings at either side of the shelf assembly. Advantageously, at the open ends of the fiber trough are fiber guide devices, which provide a smooth, rounded exit/entry openings through which fiber cables are introduced into the shelf assembly. Advantageously, fiber reels can be disposed on an external portion of the card cage assembly, such that the fiber cables can be stored.
The present invention has many advantages, such as simultaneous bi-directional access and routing to the plug-in cards in the system, while maintaining an appropriate bend radius for each fiber cable. The smooth concave surface of the fiber channels as well as the smooth, rounded surface of the fiber guide device reduces the possibility of chaffing or cutting of the fiber cables during operations or servicing of the equipment. The fiber channels and the fiber guide are modular and removable, which allows for simple redirecting of the fiber cables within the fiber trough and avoids the need to locate the fiber cables along a tortuous path to reach the mounting positions. The present invention also allows a technician the ability to access components within the card cage assembly without crossing the fiber cable paths and therefore minimizes the potential for service disruptions.
Other uses, advantages, and variations of the present invention will be apparent to one of ordinary skill in the art upon reading this disclosure and accompanying drawings.